Field of the Invention
The present invention relates to an exposure method, an exposure apparatus, and a method of manufacturing a device.
Description of the Related Art
A step-and-scan scanning exposure apparatus which exposes a substrate for each shot region performs step movement of a substrate stage in the non-scanning and scanning directions to the next shot region after exposure in one shot region ends. When the scanning exposure apparatus moves the substrate stage to the position at which exposure in the next shot region starts, it exposes the next shot region while performing scan movement of the substrate stage in the scanning direction. Japanese Patent Laid-Open No. 2000-3869 discloses a scanning exposure apparatus which pre-measures the focus position of an underlayer at an exposure position before the underlayer reaches the exposure position. The scanning exposure apparatus measures the focus position of an area to be exposed, that is, the surface shape of a substrate before exposure in the area to be exposed to adjust the focus position of the area to be exposed before the area to be exposed reaches the exposure position.
Driving of the substrate stage in the non-scanning direction in step movement need only be completed before the start of exposure in the next shot region. However, conventionally, a driving profile in the Y- (scanning) direction is generated so that pre-measure of the focus position starts after completion of step driving in the X- (non-scanning) direction, as shown in FIG. 2. This means that a driving profile is generated so that pre-measure of the focus position can be done at the central position of the shot region in the X- (non-scanning) direction.
Conventionally, because step movement in the X- (non-scanning) direction is performed during the period from the end of exposure in one shot region until pre-measure of the focus position, the time from the end of exposure in this shot region until pre-measure of the focus position is kept long in a driving profile in the Y- (scanning) direction. For example, the constant velocity interval after the end of exposure in one shot region is set long, or the acceleration (deceleration) velocity in the acceleration/deceleration interval is set low in the driving profile in the Y- (scanning) direction. Further, when an exposure process in one shot region ends, step movement in the X- (non-scanning) direction immediately starts.
In the conventional technique, until step movement in the X- (non-scanning) direction ends, pre-measure of the focus position for the next shot region cannot be done, so a long standby time is required before the start of exposure in the next shot region. It is therefore difficult for the scanning exposure apparatus in the conventional technique to obtain a high throughput.
When the positional relationship between one shot region and the next shot region changes, the position in the X- (non-scanning) direction, at which pre-measure of the focus position is performed, may change. In this case, a table representing the detection error of the focus position, which is prepared in advance, cannot be used. Also, when a plurality of types of tables representing the detection errors are prepared in correspondence with a change in pre-measure position of the focus position, the burdens of table generation and maintenance increase.